It is known to use movement dampers in a variety of assemblies to control the movement of assembly components. For example, in furniture and cabinetry it is known to use dampers for controlling movement of a drawer or a door in at least one direction. In automobiles, it is known to use dampers on glove box and counsel doors and the like. Other uses also are known.
In a known damper design, resistance to movement of a gear on a mechanism, such as an automatic closer, is provided through driving engagement between the gear of the mechanism and a gear of the damper. A rack and pinion relationship can be provided between the mechanism and damper, respectively. Resistance to rotation of the gear on the damper, which is inherent in the structure of the damper, is thereby imparted to movement of the mechanism gear, for controlling operation of the mechanism. Such damping devices are frequently referred to as gear dampers.
A gear damper is known to include a rotor rotatably held in a housing. Damping fluid in the housing around the rotor is contained by the housing, a cap and o-ring seals. A gear is attached to the rotor externally of the hosing, and the gear is drivingly connected to the gear of the mechanism for which movement control is desired.
Dampers of this type, which may include five or more separate components, are relatively expensive to manufacture and assemble. Adequate sealing is essential for continued effective operation of the damper in that if some damping fluid is allowed to leak from the housing, the damping performance of the damper is compromised. Snap together dampers are known, but have used complex labyrinth designs with pluralities of interesting concentric rings on the snap together components to contain the damping fluid. The snap features have been discontinuous about the periphery of the rotating component. Even with the complex designs, snap together dampers have been known to leak, and welding of the parts has been used to minimize the potential for leakage. Welding increases the cost to manufacture the dampers, and when the cap is made stationary by welding to the housing base, a rotor through the cap is required to support the turning gear. Seals such as o-rings are required to seal the rotor and housing interface, which add to the complexity of assembling the damper and create a source of potential leakage and wear. With the gear supported only centrally by the rotor shaft, deflection of the gear can result also from unequal internal forces from damping fluid and internal structures, such as the rotor turning therein.
Multi-component dampers, with plastic gears fitted on rotor shafts, are subject to operationally difficulties if the damper or structures to which the damper is connected becoming slightly improperly positioned. Forces against the damper can cause the gear to deflect, impacting performance and causing premature wear of the gear.
What is needed in the art is a low cost damper that is easy to assemble and reliable in performance.